The present invention relates, in general, to an injection molding machine with a control system, and more particular to an injection molding machine with a control system including a bus system.
To ensure clarity, it is necessary to establish the definition of several important terms and abbreviations that will be used throughout this disclosure. The terms “computer” and “computing unit” are used interchangeably and include central processing units (CPU), microprocessors, customer-specific computers as well as commercially available personal computers (PC), work stations and the like. CAN is short for controller area network. LAN is short for local area network.
European Pat. No. EP 0 916 466 A1 describes an injection molding machine with a control system, shown in detail in FIG. 1. The control system includes an operating unit 1 and a machine control 10 for control of an injection molding machine 40 which is shown here schematically as screw-type injection molding machine. The operating unit 1 includes a display device 3, a keyboard 4, a memory 6, a microprocessor 2 and a printer 7, whereby these components of the operating unit 1 communicate with one another via a serial CAN bus 8. Data for controlling the injection molding machine 40 can be inputted via these components and visualized by the display device 3. Furthermore, there can be provided a mass storage or the like, and programs may be installed for controlling the injection molding machine 40.
The operating unit 1 further includes an interface 5 which, on one hand, is in communication with the serial bus 8 and, on the other hand, serves as adapter for a network system 20 for communication with the machine control 10 for the injection molding machine 40. The network 20 is configured as LAN, especially Ethernet.
The machine control 10 also includes an interface 11 which, on one hand, is configured as adapter for the network 20 and, on the other hand, communicates with a serial CAN bus 17 in the machine control 10. In addition to the interface 11, the machine control includes memories 12, 14, a microprocessor 13 as well as interfaces 15, 16, whereby the mentioned components communicate with one another via the serial network 17. The interfaces 15, 16 are connected to sensors 42 and actuators 41, 43, 44 and deliver data or commands to the actuators 41, 43, 44 or receive data or commands from the sensors 42. The sensors 42 are typically temperature sensors, pressure sensors, distance sensors or the like, whereas the actuators 41, 43, 44 are typically motors or hydraulics for rotating the screw, for moving the screw, opening and closing of the mold etc.
Data are inputted by hand in this conventional control system via the keyboard 4 of the operating unit 1 and programs can also be installed. Respective data programs are then delivered via the LAN network 20 to the machine control 10 and stored there or further processed for the control. The respective commands are generated for the actuators and forwarded. Conversely, data is received by the operating unit 1 from the sensors for the machine control 10 and the LAN network 20 and visualized there.
The depicted control system is suitable for carrying out a real-time machine control because the machine control 10 directly controls the injection molding machine 40 and uses a rapidly working serial network 17. In contrast thereto, the operation of the machine control 10 via the operating unit 1 and the LAN network 20 is not implemented in real time. This network is however compatible with, e.g., the internet protocol, and further computers, e.g., a PC 30, can easily be connected to this network for visualization, documentation or the like.
Typically, the connection, for example between the keyboard 4 and the display device 3, of this conventional control system is rigid, whereby the keyboard 4 and the display device 3 use the same processor.
It would be desirable and advantageous to provide an improved injection molding machine which exhibits a greatest possible range of variation with regard to implementation.